Vapor phase operation



March 12, 1940. E. J. HOUDRY 2,192,911

VAPOR PHASE OPERATION Filed July 10, 1937 )2, k 7; Law bailing pn-rf:

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' INVENTOR EugENE LLHnudrg ATTORNEY (iii Patented Mar. 12, 1940 VAPORPHASE OPERATION Eugene J. Houdry, Havel-ford, Pa., assignor to HoudryProcess Corporation, Wilmington, Del., a corporation of DelawareApplication July 1t), 1937, Serial No. 152,879

10 Claims.

This invention relates to the division of a composite vapor stream intohigher and lower boiling parts without fractionation effected by coolingor bypartial condensation of the stream. While having features ofgeneral application, it is of particular importance in thetransformation or conversion of higher boiling hydrocarbons into lowerboiling hydrocarbons in the production of motor fuels, especially thosein the gasoline boiling range. The material, to be converted may be fromany known or suitable source such as petroleum, shale oil, bitumens,coal, lignite, and distillates, residues and derivates thereof.

In the production of motor fuels such as gasoline from higher boilinghydrocarbons only partial conversion is possible in a single operationunder the best operating conditions. To carry the reaction furthersimply means that some of the desired products are lost due to secondaryreactions which further convert the gasoline into gas and coke. Hence toobtain from a given charging stock a maximum yield of lower boilinghydrocarbons'it has been customary to separate out the lighthydrocarbons already produced and then to carry the conversion furtheron the higher boiling material. The separation has been effected by apartial condensation of the products from the transforming operation toseparate out in liquid form the higher boiling material which is thenrevaporized and subjected to further transformation either by itself orby recycling it through the initial operation with fresh chargingmaterial.

One object of the invention is to effect a separation of the lighter andthe heavier components of a composite vaporous or gaseous stream withoutcondensation. Another object is to maintain hydrocarbons undergoingconversion continuously in vapor. phase until conversion to the desiredextent has been effected. Another object is to avoid condensation ofmaterial suitable for conversion until conversion is completed. Otherobjects will be apparent from the detailed discussion which follows.

Heretofore it has been known to separate the vapors of benzene, gasolineand similar light hydrocarbons from fixed gases, natural gas, etc., byvarious so-called absorption systems utilizing liquid or solidabsorbents. The absorption is effected at low or atmospherictemperatures and the absorbed material is subsequently ejected from theabsorptive medium by a distilling operation effected by the applicationof heat or by the use of steam or hot gases. I have now discovered howto treat a composite stream of hy drocarbons of wide boiling range sothat relatively high boiling hydrocarbons such as heavy naphtha,kerosene, gas oil, fuel oil, etc. can be separated from lower boilinghydrocarbons in the gasoline boiling range and above by a somewhatsimilar operation and at temperatures where all components are in vaporphase. The separation is not clear cut but is sufliciently close topermit its use with important advantages in the conversion ofhydrocarbons.

The separation is effected by the use of porous contact material in theform of bits, fragments or molded pieces having little or no catalyticactivity but a preferential absorption for higher boiling hydrocarbons.The mass is maintained at a temperature above that required to keep thestream in vapor phase and may correspond to that of the transformingoperation as, for exam pie from 750 to 950 F. Contact of hydrocarbonswith the mass is restricted to a very short period (not in excess of afew seconds) whereupon they are promptly ejected by an extraneous mediumat high temperature such as superheated steam. The ejected higherboiling hydrocarbons are thus not only in vapor phase but may also be ata proper temperature for further conversion.

In order to illustrate the invention and the manner of its use concreteembodiments thereof are shown in the accompanying I drawing in which:

Fig. 1 is a diagrammatic view showing an application of the invention tothe thermal conversion of hydrocarbons; and

Fig. 2 is a diagrammatic view showing an application of the invention tothe catalytic transformation of hydrocarbons.

In the high temperature division of a vapor stream into low boiling andhigh boiling parts, a battery of separators, two or more in number, isutilized in order that the operation may go on continuously. In Fig. 1,three such separators, indicated by reference character 3, are shownarranged in a battery having individual valved connections at one end tovapor supply line t, to a line 5 for an ejecting medium, and to a line 6for fumes. At their opposite ends, separators i have individual valvedconnections to a line i for removing the low boiling part of the vapors,to a line 8 for removing the high boiling part of the vapors, and to aline a for supplying regenerating medium. The separators containhighlyporous material having little or no catalytic activity under theoperating conditions, but manifesting a preferential absorption for thehigh boiling parts of a vapor stream. This porous material is preferablysilicious in character and arranged in the form of bits, fragments, ormolded pieces which permit reasonably free movement therein of gaseousmaterials charged there- .to and which enable the contact material to beregenerated in place. The contact material may be composed of natural orsynthetic material, such, for example, as molded pieces of silicious orporcelaneous material, silica gel, blends of ill?! iii rial is disposed,may be of any suitable or de-' sired type. For example, they may havethe mass disposed thereinin a deep bed with the charge passingtherethrough from end to end, or various arrangements may be made fordistributing the charged fluids within the mass of contact material orfor effecting localized movement of the fluids within the mass, asdisclosed, for example, in my U. S. Patent No. 2,042,468, issued June 2,1936, or in the U. S. Patent of A. Joseph, No. 2,042,69, issued on thesame date. Heat may be supplied to the mass through the walls of thecase or by heating members embedded in the mass, as may be desired.

The vapor separators operate emciently in a Q temperature range of 750to 950 F., and this is a range in which many transforming reactions areeffected on organic materials, including hydrocarbons. The operationinvolves a short cycle, i. e., the vapor stream, which is to be dividedinto lower and higher boiling parts, is sent into one of the separatorcases 8 from supply line 6 for a few seconds, as up to 10 seconds, theporous material within the case holding back or retaining the higherboiling parts while the lower boiling parts pass through the separatorinto vent line i. The stream of vapors from line ti is then shut ofi'from this separator and sent to another, while the outlet to line I isclosed. Thereupon, the ejecting medium, such as hot gases or superheatedsteam, is sent by line 5 into the separator for a fewv seconds (the samenumber of seconds or a greater number), whereupon the higher boilingvapors retained in the mass are ejected and pass out through the valvedconnection to outlet line 8. The feeding of the vapor stream from line 4to the separator may then be resumed and the steps repeated. After atime, the porous mass in the separators loses its ability to retain thehigher boiling vapors, due to an accumulation of. gummy material in themass, whereupon purification or regeneration of the mass is necessary.This is effected by sending a regenerating medium from line 9 into thecases, which medium may be a liquid or gaseous solvent to wash out theimpurities, which escape by line 16, or the regeneration may be effectedby an oxidizing medium, such as air, which burns out the gummy materialin the mass, the fumes escaping by line 6.

The composite stream of vapors passing to line 4 may come from any knownor suitable source. For example, they may result from the transformationor conversion of lower boiling hydrocarbons into higher boilinghydrocarbons. If the conversion is effected entirely by thermal means,as by heat or heat and pressure, a tar separator, such as ID will beinterposed between the converting means and the vaporseparators,inasmuch as thermal operations produce tar and this tarry material wouldinterfere with and stop the action of the contact material in separators3. The converting means may be of any known or suitable type, such, forexample, as tube and tank, de Flores, Cross, Dubbs, etc. By way ofillustration, a still ll only is shown, but it is to be understood thata reaction chamber, flash vaporizer, or other apparatus, may be used inaddition to the still and/or tar separator.

charge passing to still ll.

The separator high boiling vapors leaving separators 3 by line 8 maypass to another still or converting apparatus such as III, as by.branched line II, or some or all of these vapors may be sent by line it?to be recycled with the fresh They may be mixed with the fresh chargebefore it enters the still, as indicated, or sent into an intermediatecoil, or through a separate coil in the same still, as may be desired.The ejecting medium supplied by line 5 will be at a pressuresufliciently high to send the vapors of the high boiling part into thesupply line to still it. For example, if steam (superheated orotherwise) is used as the ejecting agent, it may be supplied at aslightly greater pressure than is utilized in still i Las, for example,5 pounds additional pressure. If a reaction chamber follows still H,line 13 may join the line between the still and the reaction chamber anddeliver the separated high boiling-material at proper temperature andpressure for further conversion with the fresh charge coming from stillM.

Fig. 2 shows one arrangement for utilizing the invention in connectionwith catalytic cracking operations. The figure is not only diagrammaticbut also in order to make it as simple as possible only one piece ofapparatus has been indi-.

cated ineach zone. Hence it must be understood that for continuousoperation of the system there will be two or more catalyzers in eachcracking zone and one or more batteries of vapor separators. In the formshown, the fresh charge is passed into heater Ha, where the chargedmaterial is vaporized and raised to a suitable temperature which isusually not in excess of 900 F. The vaporized material goes into thefirst pass catalytic cracker 20, whence the cracked products passthrough line 4 to vapor separator 3a, whence the low boiling part willbe discharged through line la to storage or to further treatment, as infractionator H, from which the gasoline and gas will pass overheadthrough line 22, while a heavier fraction in the gas oil boiling rangewill be removed from the bottom of the fractionator through line 23.During the intermittent shut-off periods for separator 30, the highboiling part of the vapors will be ejected by an ejecting medium such assuperheated steam admitted through line 5a, the ejected higher boilingpart passing by line M for further treatment. While this higher boilingproduct could be recycled, after the manner indicated in Fig. 1, it ispreferable to send it through a second pass cracker such as 24,operating at the same or a somewhat higher temperature than the firstpass catalytic cracker 20, the cracked products from 24 passing from thelatter by line 4b for another vapor separating operation. This secondseparating operation could be effected in another vapor separator orseries of vapor separators, but, inasmuch as the arrangement in Fig. 2provides for recycling the high boiling part through the second passcatalytic cracker, these products are sent into vapor separator 3a, sothat all higher boiling parts separated from the products of bothcatalytic crackers 20 and 24 are continuously sent into and through thesecond pass cracking zone. This permits the charged material to becracked to virtual exhaustion. The catalytic crackers 20 and 24 maycorrespond to any of the forms shown in the aforesaid Houdry and Josephpatents, and the catalytic masses contained therein are preferablyactive blends of silica and alumina of natural or artificial origin,with or without the addition of other metallic compounds, includingmanganese, such as disclosed, for example, in my U. S. Patents Nos.2,078,945, and 2,078,951, both issued on May 4, 1937. In other words,the contact material in the catalytic cracking zones has a high degreeof catalytic activity as compared with the very low or negligibleactivity of the porous mass utilized in the vapor separators 3 and 3a.For a two-stage operation, such as disclosed in Fig. 2, a goodtemperature for the first pass cracker M is of the order of 825 to 850F., while the temperature of the catalytic mass in the second passcatalytic cracker 2d is generally slightly higher, as of the order of850 to 875 F. The vapor separator ta is preferably operated at atemperature which is suitable for the second pass cracking operationsuch as 850 to 875 It. If necessary, addiiional heat to bring the highboiling part of the separated vapors, passing through line to to thesecond pass cracker it, to reaction temperature may be supplied by theejecting medium admitted through line to, which is by preferencesuperheated steam.

Separators ii and to effect a rough but sufficientiy close division ofthe vapors for practical purposes, and very substantially reduce theamount of heat input necessary for further con- N the separator casesare from version of the higher boiling part of the vapors. For example,let us assume that the composite vapor stream passing to the separatorst or to contains 2% of hydrocarbon gases and 98% .normally liquidhydrocarbons in the ratio of 40:58 gallons of low boiling to highboiling hydrocarbone. The vapor stream is sent in a cycle of 2 secondsthrough vapor separators such as and to which thereafter are seconds inthe ejecting stage. The separator splits the vapor stream into two partsin the ratio of about 40:60. Some 33 gallons of hydrocarbons in thegasoline boiling range and some 6 gallons of heavier hydrocarbons are inthe low boiling part which leaves the separators by lines l or in. Thehigh boiling part, which leaves the separators by lines a or but,contains the remainder of the gasoline, which is about 7 gallons, andthe rest of the higher boillng hydrocarbons, some 52 gallons. Most ofthe gasoline in the high boiling part is heavy naphtha, which 'issusceptible of conversion into light or lower boiling products in thegasoline range, when the operation is thermal, as in Fig. l, orcatalytic, as in Fig. 2, and such proportion of naphtha is not sumcientto adversely affect the second stage cracking operation to any importantextent. Any adjustments deemed desirable in .the temperature of thevapor streams passing to separators 3 and 3a or of the vapor streamsleavlng such separators may be effected by conventional heat exchangeapparatus (not shown) in lines t, land 8 of Fig. l and in lines ta, ib,la and 8a of Fig. 2. Such temperature adjustment may also be effectedwithin or by the vapor separators themselves as previously indicatedherein.

To secure the best results from the invention, the separator casesshould be small and the vapor stream should be sent therethrough at ahigh rate during the very short periods in which they are on stream. Thelimiting factor is the avoidance of cracking in these cases. In general,to the size of catalytic cases used for the catalytic cracking .zones. Agood commercial operation is secured when the charging rate to theseparator cases (figured as ratio or volume of oil [liquid] per hour pervolume oflcontact mass) is in the range of 5:1 to 13:1.

The presentinvention is a solution, long sought, of the problem ofkeeping hydrocarbon charge continuously in vapor phase untilconversionor transformation into low boiling hydrocarbons has beeneffected to the desired extent without sacrificing in any importantdegree the light products already made in the operation. As indicated byFig. 1 the invention has immediate application to and use in existingthermal plants employing internal recycling. Only very minor changes arerequired which will pay for themselves in a very short time by theresulting economy in the operation of such plants. The preferred mannerof using the invention, however; is illustrated in Fig. 2. While thecracking zones designated as first pass and second pass may operateeither thermally or catalytically, catalytic operation in both zoneswith active blends oi silica and alumina as described is preferred inview of the higher yield and better quality of products.

It is to be understood that the embodiments of the invention hereinshown and described are for the purpose of illustration only and thatthe invention covers all changes, variations, modifications andapplications within the scope of the appended claims.

I claim as my invention:

1. Process of effecting a rough division of a composite vapor streaminto higher and lower boiling parts without fractionation by cooling orpartial condensation which comprises sending the vapor stream atelevated temperature for a few seconds into a zone containing porouscontact material maintained in the temperature range of 750 to 950 F.,said material having little or no catalytic activity at such temperatureand for such time of contact but having a preferential absorption forhigher boiling components of said vapor stream, shutting off said streamand ejecting the higher boiling components in vapor form from saidcontact material by a hot gaseous purging medium.

2. Process of efiecting a rough division of a composite vapor streaminto higher and lower boiling parts without fractionation by cooling orpartial condensation which comprises sending the vapor stream for aperiod not in excess of ten seconds into a zone containing porouscontact material maintained in the temperature range of 750 to 950 F'.,said material having little or no catalytic activity at such temperatureand for such time of contact and having the ability 'to hold back withinitself the higher boiling components of said vapor stream while lettingthe lower boiling components pass, shutting off said stream, ejectingthe higher boiling components in vapor phase from said contact materialby a hot gaseous purging medium, repeating the aforesaid steps, and fromtime to time freeing said contact material of accumulated gummy depositsresulting from a series of separating operations on said vapor stream.

3. Process of effecting a rough division of a composite vapor streaminto higher and lower boiling parts without fractionation by cooling orpartial condensation which comprises sending the vapor stream atelevated temperature for a few seconds into a zone containing poroussilicious contact material at a temperature of the order of 850 to 875F., said material having little or no catalytic activity at suchtemperature and for such time of contact but having a preferentialabsorption for higher boiling components of said 75 from said materialby a gaseous purging medium heated to about the aforesaid temperature,stopping the ejecting procedure when said material is substantiallypurged, again sending said vapor stream into said zone, and repeatingthe above steps.

4. Continuous process of effecting a rough division of a composite vaporstream into higher and lower boiling parts without fractionation bycooling or partial condensation which comprises disposing in at leasttwo zones porous contact material having a preferential absorption forhigher boilingcomponents of said vapor stream, maintaining the contactmaterial in the temperature range of 750 to 950 F., sending the vaporstream at elevated temperature into each of said zones in sequence for abrief interval during which the lower boiling components pass throughwhile the higher boiling components are retained by the porous contactmaterial, ejecting the retained higher boiling components in vapor phasefrom the contact mass in each zone by a gaseous purging medium while thevapor stream is being sent to another zone, and repeating the sendingand ejecting steps so that the separated higher and lower boilingstreams of vapors are produced in a substantially continuous manner.

5. In the conversion of higher boiling hydrocarbons into lower boilinghydrocarbons the process steps of subjecting a charge of higher boilinghydrocarbons at elevated temperature to a converting operation, and thenseparating the reaction products with the aid of contact material havinga preferential absorption for higher boiling hydrocarbons while suchreaction products are maintained at temperatures in excess of 750 F.,the separation being effected without substantial loss of heat bycontacting such reaction products for a few seconds with said contactmaterial and by promptly ejecting the hydrocar bons retained by saidmaterial by means of a gaseous purging medium, at least two bodies ofcontact material being utilized to conduct the separating step in acontinuous manner by shifting the feeding of hydrocarbons from one bodyof contact material to another and by effecting the ejecting step in theintervals between successive feedings of hydrocarbons.

6. In the conversion of higher boiling hydrocarbons into lower boilinghydrocarbons the proc ess steps of subjecting a charge of higher boilinghydrocarbons at elevated temperature to a converting operation toproduce lower boiling hydrocarbons, removing'tarry and asphalticmaterial from the products of conversion, dividing the remainingproducts while in vapor phase and maintained at conversion temperatureinto a higher boiling part and a lower boiling part by intermittentlycontacting said remaining products for a few seconds with a porous masshaving little or no catalytic activity but a preferential absorption forhigher boiling hydrocarbons and by intermittently ejecting the higherboiling hydrocarbons therefrom, and continuing the conversion of saidhigher boiling part.

'7. In the conversion of higher boiling hydrocarbons into lower boilinghydrocarbons the process steps of subjecting a charge of higher boilinghydrocarbons at elevated temperature to a converting operation toproduce lower boiling hydrocarbons, sending all the reaction productswhile in vapor phase into contact with a porous silicious mass whichretains the heavier hydrocarbons while permitting the lighterhydrocarbons to pass thereby effecting a rough separation into lighterand heavier hydrocarbons and without a drop in temperature, ejecting theheavier hydrocarbons from said mass by a hot gaseous medium, andsubjecting said ejected heavier hydrocarbons directly to anotherconversion step.

8. In the production of motor fuel the process steps of sending a chargecontaining-high boiling hydrocarbons under reaction conditions oftemperature and pressure into a reaction zone to effect partialconversion thereof into lower boiling hydrocarbons, sending all thevapor phase hydrocarbons from said conversion zone at a temperature ofat least 750 F. and in vapor phase into a separating zone containing aporous mass maintained at substantially the temperature of saidconversion zone and having a preferential absorption for higher boilinghydrocarbons, ejecting the higher boiling hydrocarbons from saidseparating zone in vapor phase without cooling the same and at suitabletemperature for further conversion, and directly continuing theconversion of said ejected higher boiling hydrocarbons.

9. In the production of motor fuel the process steps of sending a chargeof high boiling hydrocarbons under reaction conditions of temperatureand pressure into a reaction zone to effect partial conversion thereofinto lower boiling hydrocarbons, sending the hydrocarbons from saidconversion zone at a temperature above 750 F. and in vaporphaseintermittently for a few seconds into a separating zone containing aporous mass which retains the heavier hydrocarbons while permitting thelighter hydrocarbons to pass thereby effecting a rough separation intolighter and heavier hydrocarbons, intermittently ejecting the heavierhydrocarbons from said mass in vapor phase and without substantial lossof heat by a hot gaseous medium, and continuing the conversion of saidejected heavier hydrocarbons by sending them at reaction temperature andpressure to join the charge to said reaction or conversion zone.

10. In the production of motor fuel the process steps of sending acharge of high boiling hy-. drocarbons under reaction conditions oftemperature and pressure into a primary reaction zone to efiect partialconversion thereof into lower boiling hydrocarbons, making a roughseparation of the products of the reaction into lower and higher boilinghydrocarbons by sending the hydrocarbons from said primary conversionzone in vapor phase and intermittently for a few seconds into aseparating zone containing a porous mass having a preferentialabsorption for higher boiling hydrocarbons and by intermittentlyejecting the higher boiling hydrocarbons from said separating zone invapor phase and without substantial loss of heat, sending said ejectedmaterial under reaction conditions of temperature and pressure into asecond reaction zone for effecting partial conversion thereof into lowerboiling hydrocarbons, and sending the hydrocarbons from said secondreaction zone in vapor phase into said separating zone along with thehydrocarbons from said primary conversion zone whereby lower boilinghydrocarbons produced in both conversion zones are continuously removedfrom the system while uncoverted hydrocarbons in vapor EUGENE J'.HOUDRY.

